1. Field of the Invention
The present invention relates to a one-way clutch apparatus used as a backstop for an automatic transmission or the like which is employed in industrial equipment such as an agricultural machine, a motor vehicle, a construction machine and the like.
2. Related Background Art
The one-way clutch is structured such that a torque transmission member slides with respect to an inner wheel or an outer wheel at a time of idle rotation. In order to prevent an abrasion or a seizure due to a sliding motion, it is necessary to supply a lubricating fluid or oil to a surface sliding with the torque transmission member.
FIG. 3 is a cross sectional view in an axial direction which shows a lubricating structure of a conventional one-way clutch apparatus. A one-way clutch apparatus 51 is structured such that a one-way clutch 54 is arranged between an inner wheel 52 and an outer wheel 53 which are arranged coaxially. A sprag 59 is used in the torque transmission member, and this sprag 59 slides with respect to the inner wheel 52. An oil hole 58 that supplies lubricating oil toward the sliding surface is provided in the inner wheel 52.
However, in the conventional one-way clutch apparatus, since the oil hole 58 is provided on a surface that is directly exposed to a torque applied from the sprag 59, a surface pressure in the periphery of an opening portion of the oil hole 58 and in the sprag 59 positioned there tends to become high. Further, at a time of designing the one-way clutch apparatus 51, it is necessary to set a number of the sprag 59 to be more, and a cost is increased at that degree. Further, in order to stand against a high speed rotation and a high load, the one-way clutch apparatus is provided with a portion extending to a portion in an inner diameter side rather than the one-way clutch in the outer wheel so as to cover the one-way clutch, and is structured such as to be bearing supported by an inner peripheral surface of the extending portion. In this case, the oil hole 58 is omitted, it is hard to supply the lubricating oil.